High CPU on CSS11503 , with one Flow

[Sbutzek]

Hi,

I've seen some high CPU Utilisation on 2 CSS.

I've figured out, that this Utilisation was created, by a mirroring Task from a database Server.

There was one TCP Connection between 2 Servers, whitch transfered about 60 Mbit/s.

But i saw a CPU-Utilisation from about 30-40% on my SCM which passed the Traffic.

That is some thing i do not understand, because the Forwading of this Flow shoud be done in the Flow-Processor, and the CPU Utilisation which is monitored, is the Session Processor.

The Protocol was TCP 1500, which is Used by Tivoli Storage Manager.

Anybody has some Idea, how this makes so much CPU Utilisation?

The Transfer was about 4 hours, and the CPU Utilisation also.

Best regards

Sven

[Gilles Dufour]

Sven,

what CSS ?

What version ?

Anything else going on at that time that you would not be aware of ? [like did you capture 'flow activ-list'] ?

Is the traffic hitting a content rule ?

Do you have any ACL ?

Did you capture some cpu info like 'cpu hog' from llama mode or the spy report to get the list of processes using the CPU ?

Gilles.

[Sbutzek]

Hello Gilles,

may i try to show you the network design

<-> <-> <-> css <->

So the traffic was hitting 2 css.

One 11506 with 7.50 103

One 11503 with 7.50.103

The traffic was one TCP Connection between Server1 and Server2 (TCP 1500).

There are no ACL and the traffic was not hitting a content rule.

The 11506 handels normal about 30 mbit/s out, and 10 mbit/s in. Average CPU is about 1% over a day.

The 11053 handles normaly about 5mit/ out and 1 mbit/s in. Average CPU is about 4% over a day.

CPU was about 30% higher on both css, during the replicarton (~3 hours)

I did not took any debug or show commands, because i saw it on my mrtg a day later.

Also, the high cpu was only seen on the SCM Module, the second Module (IOM) was normal.

Best regads

Sven

[Gilles Dufour]

Sven,

we won't be able to tell you what this is with just that info.

If you really want to investigate further, see if you can reproduce and we will tell you what data to capture.

Thanks,

Gilles.

[Sbutzek]

Gilles,

what show commands shoud i execute, if i reproduce this?

Sven

[Sbutzek]

Hi Gilles,

i can reproduce it, but what commands shoud i execute on the css?

Sven

[Gilles Dufour]

go into debug mode and do

symbol-table load SPRITZ

shell 1 1 spy

flow-agent show active

sho system-resources

shell 1 1 spyReport

Repeat the following commands every 5 minutes or more frequently if the test takes less than 10min.

[we want to see at least 3 occurences of each command]

flow-agent show active

sho system-resources

shell 1 1 spyReport

After the test, you can do

symbol-table unload SPRITZ

Gilles.